1. Technical Field
The present invention relates to a method of controlling a robot, and a robot which acts using the method of controlling the robot.
2. Related Art
In the case of operating a robot, the rotational angle of an electric motor is detected using an angular sensor, and then the angular velocity is calculated based on the rotational angle to thereby control the operation. However, a transmission mechanism and an arm driven by the electric motor are not rigid bodies, and vibrations and torsion are generated with movement to hinder the accurate control in some cases.
Therefore, there has been proposed a robot, which calculates an amount of deflection of the arm using the acceleration detected by an inertial sensor disposed in a tip portion of the arm, and then adds the amount of deflection to the angular target value of an arm movement to thereby suppress the vibration of the arm (see, e.g., JP-A-1-173116 (Document 1)).
Further, there can also be cited the case in which it is attempted that the movement of a tip portion of an arm is detected with an inertial sensor, and the arm is driven using the detection signal of the inertial sensor to thereby make accurate positioning possible even with any vibration in the arm (see, e.g., JP-A-7-9374 (Document 2)).
In the Document 1 and Document 2 described above, the inertial sensor is disposed in the tip portion of the arm, and the movement (including the position) of the arm is controlled using the detection value of the inertial sensor. However, the sensitivity of the inertial sensor is expected to be degraded in accuracy due to the individual difference of the inertial sensor, an influence of the temperature variation, aging, and so on. There is a problem that the movement accuracy of the robot is degraded since the targeted control fails to be performed due to such degradation in accuracy of the inertial sensor as described above.